Indicator control



Feb. 8, 1955 w. J. MILLER ETAL 2,701,541

INDICATOR CONTROL Filed Aug. 3, 1953 INVENTOR. WILLIAM J. M/LLER HERBERT D. SQU/RE BURTON 14 FELDER I BY F 0 ANY United States Patent 7 Claims. (Cl. 116-124) This invention relates to an indicator control, and more ,particularly to an instrument mechanism capableof showing by visual means, the resultant eifect, when manual operation of a control member of the mechanism is alternately positioned.

Although pointers movable over a rectilinear path used in conjunction with adjustment shafts of control instruments, are well known, the present invention comprehends a manual control member in'combmation with an .illuminative element, which is capable of beingilluminated -to a contrasting degree on either side -of a virtual line of distinction. The alternate length of each contrasting region is concurrent with and consequent to angular variations in the position of thecontrol member operable by a rotatable dial.

The invention is particularly applicable to a domestic type electric stove having panel means r=for support of instruments for controlling the temperature of heating elements carried therein. Each instrument includes a shaft extending through the panel for manual control of the heatingelement, and a'verticalslot, in the panel, in which an illuminative medium may be disposed, and on which a rise in the lower illuminated region may be witnessed when the temperature of a heating unit is increased by turning the adjacent'shaft in one direction and a decrease in the vertical length of the lower "illuminated region is registered when .the shaft is turned in the opposite direction to lower the temperature of the heating element. The characteristics of such device is similar to the rise and fall in the vertical column of an expandible medium in a domestic thermometer when used for the measurement of varying temperatures. The apparatus 'is also intended to indicate the change in temperature of a gas or oilflame as the height of'such a'fiameis varied.

The operation of an electric range in which the'novel control is incorporated, is therefore simplified, especially to any one not previously accustomed to manipulating the temperature of such an appliance. Other advantages of the invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be realized and attained by means of the instrumentalities and combinations pointed out in theappen'cled claims.

In the drawings:

Fig. 1 is a fragmentary front elevational view of the instrument panel of a domestic electric 'stove in which the invention is incorporated;

Fig. 2 is a vertical section indicated by line 2-2 of Fig. 1;

Fig. 3 is a horizontal section taken on line 3-3 of Fig. 1;

Fig. 4 is a vertical section on line 4-4 of Fig. 3; and

Fig. 5 is a fragmentary perspective view of portions of the parts shown in Fig. 4.

Throughout the drawings, the referencechara'cter 6 is used to denote the instrument panel which may beformed from sheet metal, and includes a housing member 7 adjoining and to the rear of the 'stoves top or cooking surface, not shown. The housing '7 is comprised of a base wall 9, and end walls 8 placed on each vertical side of the base Wall. .From'the upper edge of the base wall 9, a depending wall 11 extends forward to an olfset' wall 12 which is inclined toward theirear whereitzis join-ablewith a top wall 13, which acts to close :the top ofithe instrument panel. Partly for the sake of embellishment, an escutchcon plate 14, having flanged edges 16 and :17 is attached to the outer surface of thewall :12.

"To the rear of wall '12, and spaced therefrom, is an instrument support plate 18 extending between the end walls 8. For illumination of the top of the stove, or objects thereon, the panel is provided with a lamp 19 preferably of the fluorescent type. It may be supported by any suitable means just below the depending wall 11. The light emitting from the lamp is shielded .from the eyes of an attendant of the stove by a lamp shade 21, preferably of sheet metal and mounted so as to extend downward from the depending wall v11 partially encasing the lamp.

The temperature of each of the heating units .is controlled by a rheostat 24 which is mounted on a boss 28 provided by a rearward deformation of theinstrument support plate 18. The means by which the rheostat is attached to the boss includes a threaded stub sleeve 29, extending over the shaft 23, outwardly from the rheostat which passes through a hole in the boss where'atanut 31 is threaded onto the sleeve. length so 'as to extend outward from the .rheostat through holes in the wall 12and'escutcheon .plate '14 to enable a control knob 22 to be placed'thereon.

Manual rotational movement of the knobs 22 is accompanied by linear variations of luminous indicator means. To understand .this novel feature, the .escutcheon plate Mhas "a slot 32 therein beside .each of the knobs 22. The slots preferably are arranged to extend vertically for .a reason later to be apparent although it is not intended to limit the disclosure to a slot arranged as indicated.

A-combination lens and Window member 43 is mounted in the slot 32, and 'thereat secured by means of notches 46 placed in the opposed ends of the lens, and into which a spring clip 48 is placed. The end portions 47 of the clip are deflected over the ends of the lens memberto resist its displacement outward from the slot. The lens membet is substantially T-shaped in cross section to provide flanged edges 44 overlying the front of the escutcheon plate 14"to prevent the lens member from passing inwardly through the slot.

In order to obtain the luminous eifect, a-beam of lightis directed on the lens member from the rear thereof; a convenient source-of light being the lamp 19.

To enable the rays of light to be directed to the lens member, a reflector is mounted upon the rear surface of the instrument support plate 18. The reflector generally the lens member after passing through opening 34 and slot 36 in the instrument support plate 18, and offset wall 12 respectively.

On passing through the opening 36, the light rays impinge on a convex surface 45 of the lens member '43, which extends throughout the vertical length of the member. The convex surface 'has a tendency to bend the light rays toward the principal axis of the lens member upon which they meet and intersect at a common point called the principal focus. The location of the principal focus is on the principal axis midway between the surface of the lens member and center 'of curvature of ;the lens surface. It is therefore understood that the resultant Width of the illuminated area of the front'window portion of the lens member depends upon the curvature of the convex lens surface.

It is desirable therefore to select a radius .of curvature for the convex lens surface so as 'to obtain a maximum beam width while maintaining the highest quality of -on the front surface if said means retards, to any extent, the transfer .of :light .therethrough. If the interceptor means is large enough, (the illumination of the The shaft 2-3 is of suificient front surface of the lens member is completely modified, but when said means is moved partially into the course of the light it produces a pair of areas of contrasting illumination and differing abruptly at a vertical line of distinction between them, the line being transversely of the lens member 43. It is an aim of the present invention to impart to the lens member an aspect resembling the rise and fall in the fluid column of a domestic thermometer as the temperature of the air around it rises or falls. This is accomplished by arranging the light intercepting means so that its movement into the course of light creates a positional variation in the line of demarcation which may be throughout the vertical length of the lens member as one region of illumination replaces the other region, and drivingly coupling said intercepting means to the shaft, so that when an operator turns the knob 22 he also witnesses a rise and/ or fall in illumination in the vertical column of light cast upon the window portion of the lens mem ber.

Although the light intercepting means may be positioned at other points throughout the course between the lamp 19 and lens member 43, it is preferably mounted in close proximity to the lens member, since the line of demarcation is then more distinct than when theh position of said means is nearer to the source of lig t.

Structurally, the light intercepting means may take the form of some material capable of interfering with but not completely stopping the flow of light to the lens member. It may therefore be of some translucent or colored transparent element such as glass or plastic material. In a model which operated satisfactorily red methacrylate or Plexiglas was used. As illustrated, it takes the form of a vane 51 (Fig. 4) having a head 52 of Width greater than the length of the slot 36 and a bearing end 53 laterally of which is a boss 54. The boss has a bore 56 axially thereof in which is received a stud 57 for pivotal support of the vane 51; the stud being integral with a shank portion 58 passing through the instrument support 18 to which said support is secured between a flange 59 and a riveted head portion 61. Intermediate the head 52 and end 53, the vane has a clearance slot 62 which is arcuate of the bore 56 and through which the shaft 23 passes freely. Also arcuate of the bore 56 is a rib or spacer 63 on the vane 51 serving to space slightly, the head 52 from the lens member 43 by engaging the wall 12 during swinging of the vane about its pivot 57.

While other means such as a crank or crank and pitman may be used to drivingly couple the shaft 23 to the vane ft, one satisfactory means involves use of a cam 64 fixed to the shaft 23 beside the vane 51. The cam 64 has a cam track 66 about its axis in which a follower 67 is received, the follower being carried by the vane 51. The formation of the cam track 66 is such that for a fixed angular motion of the shaft 23 the lens member 43 shows a variation which is linearly constant throughout its length.

As a precaution to maintain smoothness in the operation of the indicator as one of the knobs 22 is turned, a spring 63 is coiled about the boss 54. The spring has one end portion 69 bent over the top of the vane end 53 and another end portion 71 hooked in a hole 72 in the support 18. As shown, the spring 68 is under deflection so that by virtue of its tendency to un coil it biases the vane 51 about the stud 57 to urge the follower 67 into engagement with one of the walls of the cam track 67, thereby eliminating play between the wall and follower.

If desired, the escutcheon plate 14 may bear a series of graduations 73 and suitable indicia beside each f the lens members 43 to denote the temperature to which the heating element will change when the position of the knob is moved.

Although we have described one embodiment of our invention we are aware that numerous and extensive departures may be made therefrom without departing from the spirit or scope of our invention.

We claim:

1. The combination with a panel having an indicator slot therein through which a beam of light is visible and a control shaft passing through the panel adjacent the slot is operable between predetermined limits, of a vane arranged to be out of the course of the light passing through the slot when the vane is in one predetermined position and the shaft is in one of its predetermined positions, the vane being movable to another predetermined position wherein it intercepts all the light adapted to pass through the slot, a follower on the vane, and a cam plate on the shaft engaging the follower and serving when moved to move the vane longitudinally of the slot between its predetermined positions thereby to vary linearly the illumination of said slot in accordance with the extent to which the shaft is moved from either of its limits.

2. The combination with a panel having an indicator slot therein through which a beam of light is visible and a control shaft passing through the panel adjacent the slot being rotatable between predetermined limits, of a vane arranged to be out of the course of the light passing through the slot when the vane is in one predeter mined position and the shaft is in one of its predetermined positions, pivot means connected to the vane by which said vane is pivotally associated with the panel for movement of the vane, to another predetermined position wherein it intercepts all the light adapted to pass through the slot, follower means on the vane, said follower means being spaced from said pivotal means, and cam means on the shaft engaging the follower means and serving when moved to swing the vane longitudinally of the slot between its predetermined positions thereby to vary linearly the illumination of said slot in accordance with the extent to which the shaft is rotated from either of its limits.

3. The combination with a panel on the inner side of which a beam of light is directed to illuminate a slot therein beside which a control shaft passes through the panel for rotation between predetermined limits, of a vane in pivoted relationship to the panel and arranged to be out of the course of the light passing through the slot when the vane is in one predetermined position and the shaft is in one of its predetermined positions, the vane being swingable to another predetermined position wherein it intercepts all the light adapted to pass through the slot, a follower on the vane spaced from the axis thereof, a cam plate on the shaft, and resilient means coupled to the vane to bias it so that the follower operatively engages the cam thereby for the vane to be swung between its predetermined positions when the shaft is rotated to vary linearly the illumination of said slot in accordance with the extent to which the shaft is moved from either of its limits.

4. The combination with a stove panel on the inner side of which a beam of light is directed to illuminate a slot therein beside which the shaft of a rheostat passes through the panel for rotation between predetermined limits, of a colored transparent vane in pivoted relationship to the panel and arranged to be out of the course of the light passing through the slot when the vane is in one predetermined position and the shaft is in one of its predetermined positions, the vane being swingable to another predetermined position wherein it intercepts all the light adapted to pass through the slot, a follower on the vane spaced from the axis thereof, a cam plate fixed to the shaft, a cam track on one face of the plate, said follower extending into the track and receiving motion therefrom when the shaft is turned for the vane to be positively swung between its predetermined positions thereby to vary linearly the virtual colored illumination on said slot in accordance with the extent to which the rheostat is adjusted.

5. In a domestic appliance having a control panel through which a shaft extends and which may be turned within predetermined limits and adjacent to which is a slot in the panel, the combination of, illuminative means in the slot, said means being of uniform cross-section for the length of the slot and being at least translucent to a beam of light directed onto said means from the interior of the panel to render the appearance of said means luminous from outside the panel, light retarding means in pivotal association with the panel and being out of the course of the light falling on the illuminative means when said light retarding means is in one extreme predetermined position and the shaft is at one of its predetermined limits, and driving means pivotally coupled to the light retarding means at a point spaced from its axis and being coupled to the shaft in articulate relation thereto at a point spaced from said shaft to swing said light retarding means about its pivot between its predetermined positions when the shaft is turned, the light retarding means being formed and pivotally arranged to intercept the light to the illuminative means and thereon cast a shadow of altered illumination, the length of the shaded portion of the illuminative means being variable in proportion to the extent to which the shaft is turned relative to one of its limits.

6. In a domestic appliance having a control panel through which a shaft extends and which may be turned within predetermined limits and adjacent to which is a slot in the panel, the combination of, illuminative means in the slot, said means being of uniform cross-section for the length of the slot and being at least translucent to a beam of light directed onto said means from the interior of the panel to render the appearance of said means luminous from outside the panel, light retarding means in pivotal association with the panel and being out of the course of the light falling on the illuminative means when said light retarding means is in one extreme predetermined position and the shaft is at one of its predetermined limits, driving means pivotally coupled to the light retarding means at a point spaced from its axis and being coupled to the shaft in articulate relation thereto at a point spaced from said shaft to swing said light retarding means about its pivot between its predetermined positions when the shaft is turned, the light retarding means being formed and pivotally arranged to intercept the light to the illuminative means and thereon cast a shadow of altered illumination, the length of the shaded portion of the illuminative means being variable in proportion to the extent to which the shaft is turned relative to one of its limits, and a linear scale beside the illuminative means from which may be determined the angular adjustment of the shaft by noting on the scale the graduation thereon nearest to the variable edge of the shadow cast on said illuminative means.

7. In an electric stove having a horizontal cooking surface illuminated by a lamp on an instrument panel at the rear of the cooking surface and a shaft passing through the panel for its manual operation from outside the panel to adjust a heat controller within the panel for regulating cooking temperatures, the combination of, a reflector mounted behind the panel, the reflector receiving light from the lamp and deflecting it onto the slot for illumination thereof, visual means in the slot and uniform in cross-section for the length thereof and being luminous by the light from within the slot to an observer outside the panel, light retarding means in pivotal association with the panel and being out of the course of the light falling on the visual means when said light retarding means is in one extreme predetermined position and the shaft is at one of its predetermined limits, driving means pivotally coupled to the light retarding means at a point spaced from its axis and being coupled to the shaft in articulate relation thereto at a point spaced from said shaft to swing said light retarding means about its pivot between its predetermined positions when the shaft is turned, said light retarding means being formed and pivotally arranged to intercept the light to the visual means and thereon cast a shadow of altered illumination, the length of the shaded portion of the visual means being variable in proportion to the extent to which the shaft is turned relative to one of its limits, and a linear scale beside the visual means from which may be determined the angular adjustment of the shaft by noting on the scale the graduation thereon nearest to the variable edge of the shadow cast on said visual means.

References Cited in the file of this patent UNITED STATES PATENTS 1,467,853 Heinold Sept. 11, 1923 1,813,566 Corey July 7, 1931 1,975,675 Antelme Oct. 2, 1934 2,339,904 Almquist Jan. 25, 1944 

